I think positive self-talk can make a big difference to how we not only pick our way through the challenges of life, great and small, but also -crucially- how we experience ourselves as we work through said challenges. I coach myself through things which both helps me actually do the difficult thing, and also makes me feel like I'm someone who's 'got this'. It helps regulate emotions which supports physiological readiness to engage with the world. It's also about what I don't tell myself -I don't berate myself or reflect back negatively to myself the things I find hard or struggle with or am scared of. I'm not mean to myself. Essentially, I narrate my experience through a lense of positive regard.
It sits in a wider container of my general outlook, and it's become part of a sort of virtuous circle. I make small deliberate decisions about how I view the world ('people generally do / believe they do the best they can within the circumstances they find themselves in' etc, acknowledging that often, circumstances are hard and choices tough). We're not all born trusting, 'glass-half-full' people but I think we can cultivate empathy and compassion both for others and ourselves through those deliberate decisions. I work with people who are faced with seemingly insurmountable challenges and impossible choices, so its a daily practice, if you like. I include myself in this basic understanding of being deserving of kindness and patience, and it allows me to relax and unclench a bit about situations arising, about other people and possible outcomes.
Over the years, I've enjoyed therapy both in groups and individually, as well as meditation and mindfulness practices. I've found the greatest benefit of these has been to grow an awareness and acceptance of who I am in the world, what I am beyond my mind and how these experiences interact. And basic gratitude practice. Against this backdrop, my positive self-talk tends to consist of 'reminders' that, 'like waves on the ocean', events arise and fall away, I'm not identified with them but have agency to act within them. Depending on the situation, I 'talk' to myself with words of encouragement and reflecting back to myself what I observe: "Warmth, I know you're feeling sick about your meeting with the auditor. You've been sleeping badly, and spending more time than necessary going over the details, because you care. You're anxious about having missed something -that's natural. You want to project professional competence and capacity -that's good. This time next week, it'll be done. You'll be a part of the process, whatever arises, and should anything unexpected come to light, that is something you can address then. You are good at not catastrophising, keep it up."
"Warmth, you're giving yourself opportunities to be healthy and rested even though it's hard -you have a lot on. Despite everything, this week, you've x, y and even managed z. You can pick up * again next week. Well done."
And so on. Last year, in the middle of bereavement, estrangement, a tough diagnosis, separation, work challenges, all within a few months -the wheels falling off in so many areas of my life- I would breathe myself through one tiny moment at a time, by literally repeating to myself 'Love this too.' It seemed faintly ridiculous, but allowed a moment-to-moment softening and regulating, and for the anxiety or fear or sadness or anger or hurt to subside. Until it arose again. Rinse and repeat. Baby-steps until I'd moved through it, and it through me.
Not sure if that answers it. I don't stand in front of the mirror pep-talking myself explicitly, it's more like being a good companion to myself, if that makes sense, as in 'What would your dearest friend say to you in this situation?'.